<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title></title>
	</head>
	<body>
		
		<script type="text/javascript">
			
			var age = window.prompt("请输入您的年龄")
			
			console.log( typeof age);
			console.log(age);
			age = Number(age) + 5
			console.log(age);  // 25
			
		</script>
		
	
	</body>
</html>
